# Copyright 1999-2020 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

import io
import sys
import time

import portage
import portage.util.formatter as formatter
from portage import os
from portage import _encodings
from portage import _unicode_encode
from portage.output import xtermTitle

from _emerge.getloadavg import getloadavg


class JobStatusDisplay:
    _bound_properties = ("curval", "failed", "running")

    # Don't update the display unless at least this much
    # time has passed, in units of seconds.
    _min_display_latency = 2

    _default_term_codes = {
        "cr": "\r",
        "el": "\x1b[K",
        "nel": "\n",
    }

    _termcap_name_map = {
        "carriage_return": "cr",
        "clr_eol": "el",
        "newline": "nel",
    }

    def __init__(self, quiet=False, xterm_titles=True):
        object.__setattr__(self, "quiet", quiet)
        object.__setattr__(self, "xterm_titles", xterm_titles)
        object.__setattr__(self, "maxval", 0)
        object.__setattr__(self, "merges", 0)
        object.__setattr__(self, "_changed", False)
        object.__setattr__(self, "_displayed", False)
        object.__setattr__(self, "_last_display_time", 0)

        self.reset()

        isatty = (
            os.environ.get("TERM") != "dumb"
            and hasattr(self.out, "isatty")
            and self.out.isatty()
        )
        object.__setattr__(self, "_isatty", isatty)
        if not isatty or not self._init_term():
            term_codes = {}
            for k, capname in self._termcap_name_map.items():
                term_codes[k] = self._default_term_codes[capname]
            object.__setattr__(self, "_term_codes", term_codes)
        encoding = sys.getdefaultencoding()
        for k, v in self._term_codes.items():
            if not isinstance(v, str):
                self._term_codes[k] = v.decode(encoding, "replace")

        if self._isatty:
            width = portage.output.get_term_size()[1]
        else:
            width = 80
        self._set_width(width)

    def _set_width(self, width):
        if width == getattr(self, "width", None):
            return
        if width <= 0 or width > 80:
            width = 80
        object.__setattr__(self, "width", width)
        object.__setattr__(self, "_jobs_column_width", width - 32)

    @property
    def out(self):
        """Use a lazy reference to sys.stdout, in case the API consumer has
        temporarily overridden stdout."""
        return sys.stdout

    def _write(self, s):
        # avoid potential UnicodeEncodeError
        s = _unicode_encode(s, encoding=_encodings["stdio"], errors="backslashreplace")
        out = self.out.buffer
        out.write(s)
        out.flush()

    def _init_term(self):
        """
        Initialize term control codes.
        @rtype: bool
        @return: True if term codes were successfully initialized,
                False otherwise.
        """

        term_type = os.environ.get("TERM", "").strip()
        if not term_type:
            return False
        tigetstr = None

        try:
            import curses

            try:
                curses.setupterm(term_type, self.out.fileno())
                tigetstr = curses.tigetstr
            except curses.error:
                pass
        except ImportError:
            pass

        if tigetstr is None:
            return False

        term_codes = {}
        for k, capname in self._termcap_name_map.items():
            # Use _native_string for PyPy compat (bug #470258).
            code = tigetstr(portage._native_string(capname))
            if code is None:
                code = self._default_term_codes[capname]
            term_codes[k] = code
        object.__setattr__(self, "_term_codes", term_codes)
        return True

    def _format_msg(self, msg):
        return f">>> {msg}"

    def _erase(self):
        self._write(self._term_codes["carriage_return"] + self._term_codes["clr_eol"])
        self._displayed = False

    def _display(self, line):
        self._write(line)
        self._displayed = True

    def _update(self, msg):
        if not self._isatty:
            self._write(self._format_msg(msg) + self._term_codes["newline"])
            self._displayed = True
            return

        if self._displayed:
            self._erase()

        self._display(self._format_msg(msg))

    def displayMessage(self, msg):
        was_displayed = self._displayed

        if self._isatty and self._displayed:
            self._erase()

        self._write(self._format_msg(msg) + self._term_codes["newline"])
        self._displayed = False

        if was_displayed:
            self._changed = True
            self.display()

    def reset(self):
        self.maxval = 0
        self.merges = 0
        for name in self._bound_properties:
            object.__setattr__(self, name, 0)

        if self._displayed:
            self._write(self._term_codes["newline"])
            self._displayed = False

    def __setattr__(self, name, value):
        old_value = getattr(self, name)
        if value == old_value:
            return
        object.__setattr__(self, name, value)
        if name in self._bound_properties:
            self._property_change(name, old_value, value)

    def _property_change(self, name, old_value, new_value):
        self._changed = True
        self.display()

    def _load_avg_str(self):
        try:
            avg = getloadavg()
        except OSError:
            return "unknown"

        max_avg = max(avg)

        if max_avg < 10:
            return ", ".join(f"{x:.2f}" for x in avg)
        elif max_avg < 100:
            return ", ".join(f"{x:.1f}" for x in avg)
        else:
            return ", ".join(f"{x:.0f}" for x in avg)

    def display(self):
        """
        Display status on stdout, but only if something has
        changed since the last call. This always returns True,
        for continuous scheduling via timeout_add.
        """

        if self.quiet:
            return True

        current_time = time.time()
        time_delta = current_time - self._last_display_time
        if self._displayed and not self._changed:
            if not self._isatty:
                return True
            if time_delta < self._min_display_latency:
                return True

        self._last_display_time = current_time
        self._changed = False
        self._display_status()
        return True

    def _display_status(self):
        # Don't use len(self._completed_tasks) here since that also
        # can include uninstall tasks.
        curval_str = f"{self.curval}"
        maxval_str = f"{self.maxval}"
        running_str = f"{self.running}"
        failed_str = f"{self.failed}"
        load_avg_str = self._load_avg_str()

        color_output = io.StringIO()
        plain_output = io.StringIO()
        style_file = portage.output.ConsoleStyleFile(color_output)
        style_file.write_listener = plain_output
        style_writer = portage.output.StyleWriter(file=style_file, maxcol=9999)
        style_writer.style_listener = style_file.new_styles
        f = formatter.AbstractFormatter(style_writer)

        number_style = "INFORM"
        f.add_literal_data("Jobs: ")
        f.push_style(number_style)
        f.add_literal_data(curval_str)
        f.pop_style()
        f.add_literal_data(" of ")
        f.push_style(number_style)
        f.add_literal_data(maxval_str)
        f.pop_style()
        f.add_literal_data(" complete")

        if self.running:
            f.add_literal_data(", ")
            f.push_style(number_style)
            f.add_literal_data(running_str)
            f.pop_style()
            f.add_literal_data(" running")

        if self.failed:
            f.add_literal_data(", ")
            f.push_style(number_style)
            f.add_literal_data(failed_str)
            f.pop_style()
            f.add_literal_data(" failed")

        padding = self._jobs_column_width - len(plain_output.getvalue())
        if padding > 0:
            f.add_literal_data(padding * " ")

        f.add_literal_data("Load avg: ")
        f.add_literal_data(load_avg_str)

        # Truncate to fit width, to avoid making the terminal scroll if the
        # line overflows (happens when the load average is large).
        plain_output = plain_output.getvalue()
        if self._isatty and len(plain_output) > self.width:
            # Use plain_output here since it's easier to truncate
            # properly than the color output which contains console
            # color codes.
            self._update(plain_output[: self.width])
        else:
            self._update(color_output.getvalue())

        if self.xterm_titles:
            # If the HOSTNAME variable is exported, include it
            # in the xterm title, just like emergelog() does.
            # See bug #390699.
            title_str = " ".join(plain_output.split())
            hostname = os.environ.get("HOSTNAME")
            if hostname is not None:
                title_str = f"{hostname}: {title_str}"
            xtermTitle(title_str)
